Extending solomon output masks

[Byron Delabarre <byron@aztec.chemistry.McMaster.CA>]

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Hello CCP4 users - 


	I am in the throes of determining an NCS operation for my dimeric protein.  Towards this end, I am trying to manually
edit a solvent mask generated from SOLOMON to envelope what I believe is the dimer.  As things stand, crystallographic
contacts are obfuscating the true shape of the dimer - it is these contacts which I am trying to edit out of the mask.

	I used the the SLVMASK option in SOLOMON to output a mask.  I am now trying to use MAPMASK to extend this slightly
beyond my assymetric unit so that I can see the entire dimer.  However, SOLOMON and MAPMASK don't seem to get along to
well, as evidenced by this error message:

 Data line--- xyzlim 0 100 -15 82 -30 50
 Data line--- EXTEND XTAL OVERLAP
 Data line--- END
  (Q)QOPEN allocated #  1
 User:   byron                Logical Name: MSKIN1
 Status: READONLY   Filename: recent_solomon.mask

  File name for input map file on unit   1 : recent_solomon.mask
                               file size =  212224  ;  logical name MSKIN1


 Number of columns, rows, sections ...............   33   80   80
 Map mode ........................................    0
 Start and stop points on columns, rows, sections     0   32    0   79    0   79
 Grid sampling on x, y, z ........................   80   80  256
 Cell dimensions .................................  80.97 80.97 249.67 90.00 90.00 90.00
 Fast, medium, slow axes .........................    Z    X    Y
 Space-group .....................................    1
 Number of titles ................................    1

.....

  (Q)QOPEN allocated #  1
 User:   byron                Logical Name: MSKIN1
 Status: READONLY   Filename: recent_solomon.mask

 MAP/MASK READ SUCCESSFUL


 mapmask:   mapoverlap - map does not contain a whole ASU
 mapmask:   mapoverlap - map does not contain a whole ASU    


	As a quick reminder, the ASU for P43212 is 0<x<1 0<y<1 0<z<1/8th (so x=80 y=80 z=31.2 A should contain an ASU for my
cell of 80 80 249.67)

	The problem seems to be rounding errors with regards to the Z axis, as this is the only grid spacing less than 1
angstrom.  X and Y axes behave alright and can be extended properly if I use the PAD command in MAPMASK, but I can't see
anything beyond the assymetric unit along the Z direction.  Is this a quirk/bug in either SOLOMON or MAPMASK, or am I
(once again) making a foolish mistake?

	Thanks in advance for help rendered!

-- 
Byron Delabarre                  "In reciprocal space, I'm a somebody"
Department of Biochemistry
McMaster University
Hamilton, Ontario, CANADA        Phone: 905 525 9140 x22428